Trane vapor system with combination one pipe heating risers and two pipe radiators

spiro

Dripping the riser sounds like a great idea. Thank you all!!!

Can the drips of 4 risers all be connected into one pipe near the cellar ceiling before this same pipe drops into the wet return pipe or do I need to run each drip directly to the wet return pipe? If I can combine all 4 drips into one pipe before connecting to the wet return, I should be able to do this with reasonable cost.

Also, can I install the check valve in this 3/4" horizontal run in the cellar or should I install it at the top of the 2" riser on the 6th floor just below the air vent?

Fred

Yes you can tie the drips together and drop them to the wet return. The check valve needs to be at the vent(s). It should be on the same nipple as the vents so that it shuts and blocks air from entering the 2" riser when the boiler ends a cycle and you keep a vacuum. Make sure you install it in the right direction so that it lets air out when steam pushes and closes when a vacuum develops.

spiro

What brand and model check valves are recommended for this application?

Steamhead

Fred said:

Yes you can tie the drips together and drop them to the wet return.

Actually, no. You need to drop all the drips below the waterline before joining them, otherwise steam can travel thru the drip piping from one riser to another. This can cause banging and uneven heat.

If you run the drips to a dry return, each drip needs a trap so steam cannot reach the dry return.

spiro

Got it. Thanks!!!

I'm going to install the drips tomorrow and I will keep you all posted regarding the results. Once I fix the problem with the one pipe heating, if the system starts working properly without a vacuum, I will then turn my efforts to trying to get the system to work with a vacuum.

Two questions in anticipation regarding the Vacuum system:

1) What brand and model check valves should I consider using to help establish the vacuum at the top of the one-pipe riser?

2) Does a vacuum system need a vacuum breaker?

nicholas bonham-carter

No vacuum breaker needed, as you want the vacuum to persist as long as possible.
A check valve mounted horizontally, with a nearly vertical flap should be best.--NBC

spiro

Success!!!

The drip lines solved my problem. Steam is now getting to the 6th floor in the one pipe risers very quickly and I only need to run the boiler between 0.4psi and 1.0psi.

Now, the last thing I want to do is to figure out how to run the system as a Trane Vapor System under vacuum conditions, which I think is how it was intended to run when it was first installed in 1929. The problem I have is figuring out what to do with the one pipe risers? The two pipe risers have a vacuum check air vent at the dry returns (no need for vents at the main lines). This seems to create a vacuum for a short period of time in the two pipe portion of the system when the boiler turns off. Since steam moves from high pressure to low pressure, when the boiler stops running, I believe the steam from the one pipe riser (which is vented with a Gorton D at the top) drops down the riser into the steam main and back up into the two pipe riser, keeping the radiators warm longer. Is this how this system should work or should the one pipe radiator air vents be replaced with air vents that also have a vacuum check so that the entire system is then able to keep a vacuum?

nicholas bonham-carter

Those riser vents will need check valves to keep everything in a vacuum In between firings.--NBC

spiro

Agreed but should that be the goal...should I keep everything in vacuum by adding check valves to the one pipe risers? Will this be the best way to run the system and will it be the most efficient?

Fred

Great news! Glad that worked out.

nicholas bonham-carter

If you are going vacuum, then the whole system must be protected from air reentry by check valves.--NBC

spiro

Are there any check valve manufacturers that you would recommend for this application?

spiro

Can I use a thermostatic radiator trap as a vent for a steam main and also to vent the two pipe dry return. I want to use the Monash 48 since according to Dans "greening steam" book it vents such a large amount of air.

nicholas bonham-carter

I would use something like a Gorton D on each riser, with a check valve, and the monash traps on the crossovers.
It might be better to get the system venting well as a non vacuum setup first, and when you are satisfied with the performance, install the check valves later.--NBC